Percy padece dislexia y dificultades para concentrarse. Objeto de burlas por inventarse historias fantásticas, ni siquiera él mismo acaba de creérselas hasta el día que los dioses del Olimpo le revelan la verdad.After learning that he is the son of a mortal woman and Poseidon, god of the sea, twelve-year-old Percy is sent to a summer camp for demigods like himself, and joins his new friends on a quest to prevent a war between the gods.